1 // SPDX-License-Identifier: GPL-2.0-only
2 /* linux/arch/arm/mach-exynos4/mct.c
3  *
4  * Copyright (c) 2011 Samsung Electronics Co., Ltd.
5  *		http://www.samsung.com
6  *
7  * Exynos4 MCT(Multi-Core Timer) support
8 */
9 
10 #include <linux/interrupt.h>
11 #include <linux/irq.h>
12 #include <linux/err.h>
13 #include <linux/clk.h>
14 #include <linux/clockchips.h>
15 #include <linux/cpu.h>
16 #include <linux/delay.h>
17 #include <linux/percpu.h>
18 #include <linux/of.h>
19 #include <linux/of_irq.h>
20 #include <linux/of_address.h>
21 #include <linux/clocksource.h>
22 #include <linux/sched_clock.h>
23 
24 #define EXYNOS4_MCTREG(x)		(x)
25 #define EXYNOS4_MCT_G_CNT_L		EXYNOS4_MCTREG(0x100)
26 #define EXYNOS4_MCT_G_CNT_U		EXYNOS4_MCTREG(0x104)
27 #define EXYNOS4_MCT_G_CNT_WSTAT		EXYNOS4_MCTREG(0x110)
28 #define EXYNOS4_MCT_G_COMP0_L		EXYNOS4_MCTREG(0x200)
29 #define EXYNOS4_MCT_G_COMP0_U		EXYNOS4_MCTREG(0x204)
30 #define EXYNOS4_MCT_G_COMP0_ADD_INCR	EXYNOS4_MCTREG(0x208)
31 #define EXYNOS4_MCT_G_TCON		EXYNOS4_MCTREG(0x240)
32 #define EXYNOS4_MCT_G_INT_CSTAT		EXYNOS4_MCTREG(0x244)
33 #define EXYNOS4_MCT_G_INT_ENB		EXYNOS4_MCTREG(0x248)
34 #define EXYNOS4_MCT_G_WSTAT		EXYNOS4_MCTREG(0x24C)
35 #define _EXYNOS4_MCT_L_BASE		EXYNOS4_MCTREG(0x300)
36 #define EXYNOS4_MCT_L_BASE(x)		(_EXYNOS4_MCT_L_BASE + (0x100 * x))
37 #define EXYNOS4_MCT_L_MASK		(0xffffff00)
38 
39 #define MCT_L_TCNTB_OFFSET		(0x00)
40 #define MCT_L_ICNTB_OFFSET		(0x08)
41 #define MCT_L_TCON_OFFSET		(0x20)
42 #define MCT_L_INT_CSTAT_OFFSET		(0x30)
43 #define MCT_L_INT_ENB_OFFSET		(0x34)
44 #define MCT_L_WSTAT_OFFSET		(0x40)
45 #define MCT_G_TCON_START		(1 << 8)
46 #define MCT_G_TCON_COMP0_AUTO_INC	(1 << 1)
47 #define MCT_G_TCON_COMP0_ENABLE		(1 << 0)
48 #define MCT_L_TCON_INTERVAL_MODE	(1 << 2)
49 #define MCT_L_TCON_INT_START		(1 << 1)
50 #define MCT_L_TCON_TIMER_START		(1 << 0)
51 
52 #define TICK_BASE_CNT	1
53 
54 #ifdef CONFIG_ARM
55 /* Use values higher than ARM arch timer. See 6282edb72bed. */
56 #define MCT_CLKSOURCE_RATING		450
57 #define MCT_CLKEVENTS_RATING		500
58 #else
59 #define MCT_CLKSOURCE_RATING		350
60 #define MCT_CLKEVENTS_RATING		350
61 #endif
62 
63 /* There are four Global timers starting with 0 offset */
64 #define MCT_G0_IRQ	0
65 /* Local timers count starts after global timer count */
66 #define MCT_L0_IRQ	4
67 /* Max number of IRQ as per DT binding document */
68 #define MCT_NR_IRQS	20
69 
70 enum {
71 	MCT_INT_SPI,
72 	MCT_INT_PPI
73 };
74 
75 static void __iomem *reg_base;
76 static unsigned long clk_rate;
77 static unsigned int mct_int_type;
78 static int mct_irqs[MCT_NR_IRQS];
79 
80 struct mct_clock_event_device {
81 	struct clock_event_device evt;
82 	unsigned long base;
83 	/**
84 	 *  The length of the name must be adjusted if number of
85 	 *  local timer interrupts grow over two digits
86 	 */
87 	char name[11];
88 };
89 
90 static void exynos4_mct_write(unsigned int value, unsigned long offset)
91 {
92 	unsigned long stat_addr;
93 	u32 mask;
94 	u32 i;
95 
96 	writel_relaxed(value, reg_base + offset);
97 
98 	if (likely(offset >= EXYNOS4_MCT_L_BASE(0))) {
99 		stat_addr = (offset & EXYNOS4_MCT_L_MASK) + MCT_L_WSTAT_OFFSET;
100 		switch (offset & ~EXYNOS4_MCT_L_MASK) {
101 		case MCT_L_TCON_OFFSET:
102 			mask = 1 << 3;		/* L_TCON write status */
103 			break;
104 		case MCT_L_ICNTB_OFFSET:
105 			mask = 1 << 1;		/* L_ICNTB write status */
106 			break;
107 		case MCT_L_TCNTB_OFFSET:
108 			mask = 1 << 0;		/* L_TCNTB write status */
109 			break;
110 		default:
111 			return;
112 		}
113 	} else {
114 		switch (offset) {
115 		case EXYNOS4_MCT_G_TCON:
116 			stat_addr = EXYNOS4_MCT_G_WSTAT;
117 			mask = 1 << 16;		/* G_TCON write status */
118 			break;
119 		case EXYNOS4_MCT_G_COMP0_L:
120 			stat_addr = EXYNOS4_MCT_G_WSTAT;
121 			mask = 1 << 0;		/* G_COMP0_L write status */
122 			break;
123 		case EXYNOS4_MCT_G_COMP0_U:
124 			stat_addr = EXYNOS4_MCT_G_WSTAT;
125 			mask = 1 << 1;		/* G_COMP0_U write status */
126 			break;
127 		case EXYNOS4_MCT_G_COMP0_ADD_INCR:
128 			stat_addr = EXYNOS4_MCT_G_WSTAT;
129 			mask = 1 << 2;		/* G_COMP0_ADD_INCR w status */
130 			break;
131 		case EXYNOS4_MCT_G_CNT_L:
132 			stat_addr = EXYNOS4_MCT_G_CNT_WSTAT;
133 			mask = 1 << 0;		/* G_CNT_L write status */
134 			break;
135 		case EXYNOS4_MCT_G_CNT_U:
136 			stat_addr = EXYNOS4_MCT_G_CNT_WSTAT;
137 			mask = 1 << 1;		/* G_CNT_U write status */
138 			break;
139 		default:
140 			return;
141 		}
142 	}
143 
144 	/* Wait maximum 1 ms until written values are applied */
145 	for (i = 0; i < loops_per_jiffy / 1000 * HZ; i++)
146 		if (readl_relaxed(reg_base + stat_addr) & mask) {
147 			writel_relaxed(mask, reg_base + stat_addr);
148 			return;
149 		}
150 
151 	panic("MCT hangs after writing %d (offset:0x%lx)\n", value, offset);
152 }
153 
154 /* Clocksource handling */
155 static void exynos4_mct_frc_start(void)
156 {
157 	u32 reg;
158 
159 	reg = readl_relaxed(reg_base + EXYNOS4_MCT_G_TCON);
160 	reg |= MCT_G_TCON_START;
161 	exynos4_mct_write(reg, EXYNOS4_MCT_G_TCON);
162 }
163 
164 /**
165  * exynos4_read_count_64 - Read all 64-bits of the global counter
166  *
167  * This will read all 64-bits of the global counter taking care to make sure
168  * that the upper and lower half match.  Note that reading the MCT can be quite
169  * slow (hundreds of nanoseconds) so you should use the 32-bit (lower half
170  * only) version when possible.
171  *
172  * Returns the number of cycles in the global counter.
173  */
174 static u64 exynos4_read_count_64(void)
175 {
176 	unsigned int lo, hi;
177 	u32 hi2 = readl_relaxed(reg_base + EXYNOS4_MCT_G_CNT_U);
178 
179 	do {
180 		hi = hi2;
181 		lo = readl_relaxed(reg_base + EXYNOS4_MCT_G_CNT_L);
182 		hi2 = readl_relaxed(reg_base + EXYNOS4_MCT_G_CNT_U);
183 	} while (hi != hi2);
184 
185 	return ((u64)hi << 32) | lo;
186 }
187 
188 /**
189  * exynos4_read_count_32 - Read the lower 32-bits of the global counter
190  *
191  * This will read just the lower 32-bits of the global counter.  This is marked
192  * as notrace so it can be used by the scheduler clock.
193  *
194  * Returns the number of cycles in the global counter (lower 32 bits).
195  */
196 static u32 notrace exynos4_read_count_32(void)
197 {
198 	return readl_relaxed(reg_base + EXYNOS4_MCT_G_CNT_L);
199 }
200 
201 static u64 exynos4_frc_read(struct clocksource *cs)
202 {
203 	return exynos4_read_count_32();
204 }
205 
206 static void exynos4_frc_resume(struct clocksource *cs)
207 {
208 	exynos4_mct_frc_start();
209 }
210 
211 static struct clocksource mct_frc = {
212 	.name		= "mct-frc",
213 	.rating		= MCT_CLKSOURCE_RATING,
214 	.read		= exynos4_frc_read,
215 	.mask		= CLOCKSOURCE_MASK(32),
216 	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
217 	.resume		= exynos4_frc_resume,
218 };
219 
220 static u64 notrace exynos4_read_sched_clock(void)
221 {
222 	return exynos4_read_count_32();
223 }
224 
225 #if defined(CONFIG_ARM)
226 static struct delay_timer exynos4_delay_timer;
227 
228 static cycles_t exynos4_read_current_timer(void)
229 {
230 	BUILD_BUG_ON_MSG(sizeof(cycles_t) != sizeof(u32),
231 			 "cycles_t needs to move to 32-bit for ARM64 usage");
232 	return exynos4_read_count_32();
233 }
234 #endif
235 
236 static int __init exynos4_clocksource_init(void)
237 {
238 	exynos4_mct_frc_start();
239 
240 #if defined(CONFIG_ARM)
241 	exynos4_delay_timer.read_current_timer = &exynos4_read_current_timer;
242 	exynos4_delay_timer.freq = clk_rate;
243 	register_current_timer_delay(&exynos4_delay_timer);
244 #endif
245 
246 	if (clocksource_register_hz(&mct_frc, clk_rate))
247 		panic("%s: can't register clocksource\n", mct_frc.name);
248 
249 	sched_clock_register(exynos4_read_sched_clock, 32, clk_rate);
250 
251 	return 0;
252 }
253 
254 static void exynos4_mct_comp0_stop(void)
255 {
256 	unsigned int tcon;
257 
258 	tcon = readl_relaxed(reg_base + EXYNOS4_MCT_G_TCON);
259 	tcon &= ~(MCT_G_TCON_COMP0_ENABLE | MCT_G_TCON_COMP0_AUTO_INC);
260 
261 	exynos4_mct_write(tcon, EXYNOS4_MCT_G_TCON);
262 	exynos4_mct_write(0, EXYNOS4_MCT_G_INT_ENB);
263 }
264 
265 static void exynos4_mct_comp0_start(bool periodic, unsigned long cycles)
266 {
267 	unsigned int tcon;
268 	u64 comp_cycle;
269 
270 	tcon = readl_relaxed(reg_base + EXYNOS4_MCT_G_TCON);
271 
272 	if (periodic) {
273 		tcon |= MCT_G_TCON_COMP0_AUTO_INC;
274 		exynos4_mct_write(cycles, EXYNOS4_MCT_G_COMP0_ADD_INCR);
275 	}
276 
277 	comp_cycle = exynos4_read_count_64() + cycles;
278 	exynos4_mct_write((u32)comp_cycle, EXYNOS4_MCT_G_COMP0_L);
279 	exynos4_mct_write((u32)(comp_cycle >> 32), EXYNOS4_MCT_G_COMP0_U);
280 
281 	exynos4_mct_write(0x1, EXYNOS4_MCT_G_INT_ENB);
282 
283 	tcon |= MCT_G_TCON_COMP0_ENABLE;
284 	exynos4_mct_write(tcon , EXYNOS4_MCT_G_TCON);
285 }
286 
287 static int exynos4_comp_set_next_event(unsigned long cycles,
288 				       struct clock_event_device *evt)
289 {
290 	exynos4_mct_comp0_start(false, cycles);
291 
292 	return 0;
293 }
294 
295 static int mct_set_state_shutdown(struct clock_event_device *evt)
296 {
297 	exynos4_mct_comp0_stop();
298 	return 0;
299 }
300 
301 static int mct_set_state_periodic(struct clock_event_device *evt)
302 {
303 	unsigned long cycles_per_jiffy;
304 
305 	cycles_per_jiffy = (((unsigned long long)NSEC_PER_SEC / HZ * evt->mult)
306 			    >> evt->shift);
307 	exynos4_mct_comp0_stop();
308 	exynos4_mct_comp0_start(true, cycles_per_jiffy);
309 	return 0;
310 }
311 
312 static struct clock_event_device mct_comp_device = {
313 	.name			= "mct-comp",
314 	.features		= CLOCK_EVT_FEAT_PERIODIC |
315 				  CLOCK_EVT_FEAT_ONESHOT,
316 	.rating			= 250,
317 	.set_next_event		= exynos4_comp_set_next_event,
318 	.set_state_periodic	= mct_set_state_periodic,
319 	.set_state_shutdown	= mct_set_state_shutdown,
320 	.set_state_oneshot	= mct_set_state_shutdown,
321 	.set_state_oneshot_stopped = mct_set_state_shutdown,
322 	.tick_resume		= mct_set_state_shutdown,
323 };
324 
325 static irqreturn_t exynos4_mct_comp_isr(int irq, void *dev_id)
326 {
327 	struct clock_event_device *evt = dev_id;
328 
329 	exynos4_mct_write(0x1, EXYNOS4_MCT_G_INT_CSTAT);
330 
331 	evt->event_handler(evt);
332 
333 	return IRQ_HANDLED;
334 }
335 
336 static int exynos4_clockevent_init(void)
337 {
338 	mct_comp_device.cpumask = cpumask_of(0);
339 	clockevents_config_and_register(&mct_comp_device, clk_rate,
340 					0xf, 0xffffffff);
341 	if (request_irq(mct_irqs[MCT_G0_IRQ], exynos4_mct_comp_isr,
342 			IRQF_TIMER | IRQF_IRQPOLL, "mct_comp_irq",
343 			&mct_comp_device))
344 		pr_err("%s: request_irq() failed\n", "mct_comp_irq");
345 
346 	return 0;
347 }
348 
349 static DEFINE_PER_CPU(struct mct_clock_event_device, percpu_mct_tick);
350 
351 /* Clock event handling */
352 static void exynos4_mct_tick_stop(struct mct_clock_event_device *mevt)
353 {
354 	unsigned long tmp;
355 	unsigned long mask = MCT_L_TCON_INT_START | MCT_L_TCON_TIMER_START;
356 	unsigned long offset = mevt->base + MCT_L_TCON_OFFSET;
357 
358 	tmp = readl_relaxed(reg_base + offset);
359 	if (tmp & mask) {
360 		tmp &= ~mask;
361 		exynos4_mct_write(tmp, offset);
362 	}
363 }
364 
365 static void exynos4_mct_tick_start(unsigned long cycles,
366 				   struct mct_clock_event_device *mevt)
367 {
368 	unsigned long tmp;
369 
370 	exynos4_mct_tick_stop(mevt);
371 
372 	tmp = (1 << 31) | cycles;	/* MCT_L_UPDATE_ICNTB */
373 
374 	/* update interrupt count buffer */
375 	exynos4_mct_write(tmp, mevt->base + MCT_L_ICNTB_OFFSET);
376 
377 	/* enable MCT tick interrupt */
378 	exynos4_mct_write(0x1, mevt->base + MCT_L_INT_ENB_OFFSET);
379 
380 	tmp = readl_relaxed(reg_base + mevt->base + MCT_L_TCON_OFFSET);
381 	tmp |= MCT_L_TCON_INT_START | MCT_L_TCON_TIMER_START |
382 	       MCT_L_TCON_INTERVAL_MODE;
383 	exynos4_mct_write(tmp, mevt->base + MCT_L_TCON_OFFSET);
384 }
385 
386 static void exynos4_mct_tick_clear(struct mct_clock_event_device *mevt)
387 {
388 	/* Clear the MCT tick interrupt */
389 	if (readl_relaxed(reg_base + mevt->base + MCT_L_INT_CSTAT_OFFSET) & 1)
390 		exynos4_mct_write(0x1, mevt->base + MCT_L_INT_CSTAT_OFFSET);
391 }
392 
393 static int exynos4_tick_set_next_event(unsigned long cycles,
394 				       struct clock_event_device *evt)
395 {
396 	struct mct_clock_event_device *mevt;
397 
398 	mevt = container_of(evt, struct mct_clock_event_device, evt);
399 	exynos4_mct_tick_start(cycles, mevt);
400 	return 0;
401 }
402 
403 static int set_state_shutdown(struct clock_event_device *evt)
404 {
405 	struct mct_clock_event_device *mevt;
406 
407 	mevt = container_of(evt, struct mct_clock_event_device, evt);
408 	exynos4_mct_tick_stop(mevt);
409 	exynos4_mct_tick_clear(mevt);
410 	return 0;
411 }
412 
413 static int set_state_periodic(struct clock_event_device *evt)
414 {
415 	struct mct_clock_event_device *mevt;
416 	unsigned long cycles_per_jiffy;
417 
418 	mevt = container_of(evt, struct mct_clock_event_device, evt);
419 	cycles_per_jiffy = (((unsigned long long)NSEC_PER_SEC / HZ * evt->mult)
420 			    >> evt->shift);
421 	exynos4_mct_tick_stop(mevt);
422 	exynos4_mct_tick_start(cycles_per_jiffy, mevt);
423 	return 0;
424 }
425 
426 static irqreturn_t exynos4_mct_tick_isr(int irq, void *dev_id)
427 {
428 	struct mct_clock_event_device *mevt = dev_id;
429 	struct clock_event_device *evt = &mevt->evt;
430 
431 	/*
432 	 * This is for supporting oneshot mode.
433 	 * Mct would generate interrupt periodically
434 	 * without explicit stopping.
435 	 */
436 	if (!clockevent_state_periodic(&mevt->evt))
437 		exynos4_mct_tick_stop(mevt);
438 
439 	exynos4_mct_tick_clear(mevt);
440 
441 	evt->event_handler(evt);
442 
443 	return IRQ_HANDLED;
444 }
445 
446 static int exynos4_mct_starting_cpu(unsigned int cpu)
447 {
448 	struct mct_clock_event_device *mevt =
449 		per_cpu_ptr(&percpu_mct_tick, cpu);
450 	struct clock_event_device *evt = &mevt->evt;
451 
452 	mevt->base = EXYNOS4_MCT_L_BASE(cpu);
453 	snprintf(mevt->name, sizeof(mevt->name), "mct_tick%d", cpu);
454 
455 	evt->name = mevt->name;
456 	evt->cpumask = cpumask_of(cpu);
457 	evt->set_next_event = exynos4_tick_set_next_event;
458 	evt->set_state_periodic = set_state_periodic;
459 	evt->set_state_shutdown = set_state_shutdown;
460 	evt->set_state_oneshot = set_state_shutdown;
461 	evt->set_state_oneshot_stopped = set_state_shutdown;
462 	evt->tick_resume = set_state_shutdown;
463 	evt->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT |
464 			CLOCK_EVT_FEAT_PERCPU;
465 	evt->rating = MCT_CLKEVENTS_RATING;
466 
467 	exynos4_mct_write(TICK_BASE_CNT, mevt->base + MCT_L_TCNTB_OFFSET);
468 
469 	if (mct_int_type == MCT_INT_SPI) {
470 
471 		if (evt->irq == -1)
472 			return -EIO;
473 
474 		irq_force_affinity(evt->irq, cpumask_of(cpu));
475 		enable_irq(evt->irq);
476 	} else {
477 		enable_percpu_irq(mct_irqs[MCT_L0_IRQ], 0);
478 	}
479 	clockevents_config_and_register(evt, clk_rate / (TICK_BASE_CNT + 1),
480 					0xf, 0x7fffffff);
481 
482 	return 0;
483 }
484 
485 static int exynos4_mct_dying_cpu(unsigned int cpu)
486 {
487 	struct mct_clock_event_device *mevt =
488 		per_cpu_ptr(&percpu_mct_tick, cpu);
489 	struct clock_event_device *evt = &mevt->evt;
490 
491 	evt->set_state_shutdown(evt);
492 	if (mct_int_type == MCT_INT_SPI) {
493 		if (evt->irq != -1)
494 			disable_irq_nosync(evt->irq);
495 		exynos4_mct_write(0x1, mevt->base + MCT_L_INT_CSTAT_OFFSET);
496 	} else {
497 		disable_percpu_irq(mct_irqs[MCT_L0_IRQ]);
498 	}
499 	return 0;
500 }
501 
502 static int __init exynos4_timer_resources(struct device_node *np)
503 {
504 	struct clk *mct_clk, *tick_clk;
505 
506 	reg_base = of_iomap(np, 0);
507 	if (!reg_base)
508 		panic("%s: unable to ioremap mct address space\n", __func__);
509 
510 	tick_clk = of_clk_get_by_name(np, "fin_pll");
511 	if (IS_ERR(tick_clk))
512 		panic("%s: unable to determine tick clock rate\n", __func__);
513 	clk_rate = clk_get_rate(tick_clk);
514 
515 	mct_clk = of_clk_get_by_name(np, "mct");
516 	if (IS_ERR(mct_clk))
517 		panic("%s: unable to retrieve mct clock instance\n", __func__);
518 	clk_prepare_enable(mct_clk);
519 
520 	return 0;
521 }
522 
523 static int __init exynos4_timer_interrupts(struct device_node *np,
524 					   unsigned int int_type)
525 {
526 	int nr_irqs, i, err, cpu;
527 
528 	mct_int_type = int_type;
529 
530 	/* This driver uses only one global timer interrupt */
531 	mct_irqs[MCT_G0_IRQ] = irq_of_parse_and_map(np, MCT_G0_IRQ);
532 
533 	/*
534 	 * Find out the number of local irqs specified. The local
535 	 * timer irqs are specified after the four global timer
536 	 * irqs are specified.
537 	 */
538 	nr_irqs = of_irq_count(np);
539 	if (nr_irqs > ARRAY_SIZE(mct_irqs)) {
540 		pr_err("exynos-mct: too many (%d) interrupts configured in DT\n",
541 			nr_irqs);
542 		nr_irqs = ARRAY_SIZE(mct_irqs);
543 	}
544 	for (i = MCT_L0_IRQ; i < nr_irqs; i++)
545 		mct_irqs[i] = irq_of_parse_and_map(np, i);
546 
547 	if (mct_int_type == MCT_INT_PPI) {
548 
549 		err = request_percpu_irq(mct_irqs[MCT_L0_IRQ],
550 					 exynos4_mct_tick_isr, "MCT",
551 					 &percpu_mct_tick);
552 		WARN(err, "MCT: can't request IRQ %d (%d)\n",
553 		     mct_irqs[MCT_L0_IRQ], err);
554 	} else {
555 		for_each_possible_cpu(cpu) {
556 			int mct_irq;
557 			struct mct_clock_event_device *pcpu_mevt =
558 				per_cpu_ptr(&percpu_mct_tick, cpu);
559 
560 			pcpu_mevt->evt.irq = -1;
561 			if (MCT_L0_IRQ + cpu >= ARRAY_SIZE(mct_irqs))
562 				break;
563 			mct_irq = mct_irqs[MCT_L0_IRQ + cpu];
564 
565 			irq_set_status_flags(mct_irq, IRQ_NOAUTOEN);
566 			if (request_irq(mct_irq,
567 					exynos4_mct_tick_isr,
568 					IRQF_TIMER | IRQF_NOBALANCING,
569 					pcpu_mevt->name, pcpu_mevt)) {
570 				pr_err("exynos-mct: cannot register IRQ (cpu%d)\n",
571 									cpu);
572 
573 				continue;
574 			}
575 			pcpu_mevt->evt.irq = mct_irq;
576 		}
577 	}
578 
579 	/* Install hotplug callbacks which configure the timer on this CPU */
580 	err = cpuhp_setup_state(CPUHP_AP_EXYNOS4_MCT_TIMER_STARTING,
581 				"clockevents/exynos4/mct_timer:starting",
582 				exynos4_mct_starting_cpu,
583 				exynos4_mct_dying_cpu);
584 	if (err)
585 		goto out_irq;
586 
587 	return 0;
588 
589 out_irq:
590 	if (mct_int_type == MCT_INT_PPI) {
591 		free_percpu_irq(mct_irqs[MCT_L0_IRQ], &percpu_mct_tick);
592 	} else {
593 		for_each_possible_cpu(cpu) {
594 			struct mct_clock_event_device *pcpu_mevt =
595 				per_cpu_ptr(&percpu_mct_tick, cpu);
596 
597 			if (pcpu_mevt->evt.irq != -1) {
598 				free_irq(pcpu_mevt->evt.irq, pcpu_mevt);
599 				pcpu_mevt->evt.irq = -1;
600 			}
601 		}
602 	}
603 	return err;
604 }
605 
606 static int __init mct_init_dt(struct device_node *np, unsigned int int_type)
607 {
608 	int ret;
609 
610 	ret = exynos4_timer_resources(np);
611 	if (ret)
612 		return ret;
613 
614 	ret = exynos4_timer_interrupts(np, int_type);
615 	if (ret)
616 		return ret;
617 
618 	ret = exynos4_clocksource_init();
619 	if (ret)
620 		return ret;
621 
622 	return exynos4_clockevent_init();
623 }
624 
625 
626 static int __init mct_init_spi(struct device_node *np)
627 {
628 	return mct_init_dt(np, MCT_INT_SPI);
629 }
630 
631 static int __init mct_init_ppi(struct device_node *np)
632 {
633 	return mct_init_dt(np, MCT_INT_PPI);
634 }
635 TIMER_OF_DECLARE(exynos4210, "samsung,exynos4210-mct", mct_init_spi);
636 TIMER_OF_DECLARE(exynos4412, "samsung,exynos4412-mct", mct_init_ppi);
637